HDI (High Density Interconnect) circuits of the type comprising a plurality of interconnected circuit chips mounted on a substrate where the chips are interconnected by a metallized pattern created on a polymer overlayer are described by Eichelberger et al. in a commonly assigned U.S. Pat. No. 4,783,695, issued Nov. 8, 1988 and incorporated herein by reference. Typically, the metallized pattern is formed by a computer-controlled laser lithography system, described in a commonly assigned U.S. Pat. No. 4,835,704, issued May 30, 1989 and incorporated herein by reference. Typically, a high density interconnect structure employs between thirty and fifty or more integrated circuit chips that are assembled and interconnected on a single HDI substrate having a width and length of about 50 millimeters (mm) and a thickness of about 1.27 mm.
The aforementioned HDI structure can be disassembled for repair or replacement of a faulty component and reassembled without significant risk to the good components incorporated within the system. Ease of repairability is an important consideration where fifty or more chips having a cost of as much as $2000 each may be supported on a single substrate. Exemplary testing and repair techniques are disclosed by Eichelberger et al. in U.S. Pat. Nos. 4,878,991, issued Nov. 7, 1989; 4,884,122, issued Nov. 28, 1898 and 4,937,203, issued Jun. 26, 1990, all incorporated herein by reference.
An important objective of the HDI technology is to produce flexible HDI circuit packages or modules that contain integrated circuit chips or dice of uniform thicknesses. Employment of uniformly thick dice provides a practical method by which HDI circuit packages can be mass produced, since it allows standardization of die pockets in which the dice are positioned in the substrates generally used for typical HDI circuit packages.